The objective of this project is to use biochemical, morphological and cell fractionation techniques to analyze structurally and functionally the integrative mechanism by which hormones regulate fat cell metabolism. In particular, the mechanism of insulin action is the primary object of the study. Major focus will be on: 1. Subcellular localization insulin receptors and degradation systems, both biochemically and electron microscopically. 2. The role of a plasma membrane, insulin sensitive ATP utilizing enzyme system in the mechanism of insulin action. 3. The role of calcium in the mechanism of insulin action and the control of its subcellular distribution by insulin. BIBLIOGRAPHIC REFERENCES: Williams, L.T., Jarett, L., and Lefkowitz, R.J.: Adipocyte B-adrenergic receptors: identification and subcellular localization by (-) 3H alprenolol binding. J. of Biol. Chem. 251:3096, 1976. McDonald, J.M., Bruns, D.E. and Jarett, L.: The characterization of calcium binding to adipocyte plasma membranes. J. Biol. Chem. 251:5345, 1976.